The present invention generally relates to capacitors and more particularly, to a multiple feedthrough-capacitor unit provided with a plurality of feedthrough-capacitors, which is used as a noise filter for various electrical circuits.
Conventionally, in feedthrough-capacitors to be used as noise filters, it has been generally so arranged that inner and outer electrodes are, respectively, provided on inner and outer peripheral surfaces of each of cylindrical capacitor bodies made of ceramics, etc. such that the inner and outer electrodes are, respectively, connected, through solder, to a feedthrough-terminal extending through each of the capacitor bodies and a grounding terminal. Meanwhile, in electric appliances such as tuners of television sets, stereo receivers, etc., a plurality of the feedthrough-capacitors of the above described type are used at a time in some cases, in which cases it is desirable to form the plurality of the feedthrough-capacitors into a unitary member from the standpoint of saving of space required therefor.
Conventionally, in a multiple feedthrough-capacitor unit provided with a plurality of the feedthrough-capacitors, it has been so arranged that capacitor bodies are sequentially, respectively, fitted into through-holes provided, at a predetermined interval, on a metallic substrate and feedthrough-terminals are, respectively, inserted through through-openings each provided on each of the capacitor bodies such that the capacitor bodies are soldered to the metallic substrate and the feedthrough-terminals.
However, the known multiple feedthrough-capacitor unit has such inconveniences that a jig for positioning, at an accurate interval, the capacitor bodies soldered to the metallic substrate and a jig for bringing the feedthrough-terminals into alignment with the capacitor bodies, respectively are required to be provided.
Moreover, the known multiple feedthrough-capacitor unit has such disadvantages that it is extremely troublesome to solder the capacitor bodies to the metallic substrate through positioning of the capacitor bodies by the use of such jigs and it is difficult to perform automatic assembly of the known multiple feedthrough-capacitor unit, thereby resulting in increase in cost of assembly thereof.
Meanwhile, in the case where ceramics is used as dielectric of the capacitor bodies, the known multiple feedthrough-capacitor unit has been disadvantageous in that, when a soldering bit is brought into direct contact with the dielectric at the time of soldering of the feedthrough-terminals, the dielectric may be cracked by the thermal impulse.
Furthermore, conventionally, in another multiple feedthrough-capacitor unit, it has been so arranged as shown in FIG. 1 that, at the time of molding of a plate 1 made of electrically insulative synthetic resin, a plurality of feedthrough-terminals 2 are vertically insert molded, at a predetermined interval, into the plate 1, while a plurality of inner electrodes (not shown) each provided on an inner peripheral surface of each of capacitor bodies 3 are, respectively, soldered to the feedthrough-terminals 2. In the case where the prior art multiple feedthrough-capacitor unit is mounted on a grounding terminal strip 4, it has been so arranged that the capacitor bodies 3 are fitted into through-holes (not shown) provided, at the predetermined interval, on the grounding terminal strip 4, while a plurality of outer electrodes (not shown) each provided on an outer peripheral surface of each of the capacitor bodies 3 are, respectively, soldered to the grounding terminal strip 4 by dip soldering.
However, the prior art multiple feedthrough-capacitor unit has such inconveniences that, since the plate 1 is not secured to the grounding terminal strip 4, the grounding terminal strip 4 is caused to slip off the capacitor bodies 3 or is removed from the capacitor bodies 3 prior to curing of solder of the dip soldering.
Moreover, the prior art multiple feedthrough-capacitor unit has such a disadvantage that solder for bonding each of the inner electrodes to each of the feedthrough-terminals 2 is molten again by heat due to the dip soldering with the result that the capacitor bodies 3 are caused to slip off the feedthrough-terminals 2, respectively.